Coalescence of gas bubbles in aqueous solutions of inorganic electrolytes

Marrucci, G.; Nicodemo, L.

doi:10.1016/0009-2509(67)80190-8

Cited by 288 publications

(162 citation statements)

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“…Small bubbles remain spherical as a result of high surface tension and their coalescence can be neglected [21]. This is believed to be a result of repulsive electrical forces acting between the bubbles [22]. 4.…”

Section: Model Assumptions and Developmentmentioning

confidence: 99%

Modelling the effects of oxygen evolution in the all-vanadium redox flow battery

Al-Fetlawi

Shah

Walsh

2010

Electrochimica Acta

211

132

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a b s t r a c tThe impact of oxygen evolution and bubble formation on the performance of an all-vanadium redox flow battery is investigated using a two-dimensional, non-isothermal model. The model is based on mass, charge, energy and momentum conservation, together with a kinetic model for the redox and gas-evolving reactions. The multi-phase mixture model is used to describe the transport of oxygen in the form of gas bubbles. Numerical simulations are compared to experimental data, demonstrating good agreement. Parametric studies are performed to investigate the effects of changes in the operating temperature, electrolyte flow rate and bubble diameter on the extent of oxygen evolution. Increasing the electrolyte flow rate is found to reduce the volume of the oxygen gas evolved in the positive electrode. A larger bubble diameter is demonstrated to increase the buoyancy force exerted on the bubbles, leading to a faster slip velocity and a lower gas volume fraction. Substantial changes are observed over the range of reported bubble diameters. Increasing the operating temperature was found to increase the gas volume as a result of the enhanced rate of O 2 evolution. The charge efficiency of the cell drops markedly as a consequence.

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Section: Model Assumptions and Developmentmentioning

confidence: 99%

Modelling the effects of oxygen evolution in the all-vanadium redox flow battery

Al-Fetlawi

Shah

Walsh

2010

Electrochimica Acta

211

132

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“…En effet, le chlorure de sodium augmente la tension superficielle, ce qui rigidifie l'interface gaz liquide et, par conséquent, limite la coalescence des bulles de gaz (KOIDE et al, 1968;MARRUCCI et NICODEMO, 1967;OLIVEIRA et al, 1999;STRICKLAND, 1980). La vitesse ascensionnelle des petites bulles est plus faible que celle des bulles plus larges (BRANDON et al, 1985).…”

Section: Résultats Et Discussionunclassified

Étude comparative de l’électrocoagulation et de la coagulation floculation vis-à-vis de la déstabilisation d’une émulsion d’huile de coupe

Aoudjehane

Rezzouk

Kellil

et al. 2010

rseau

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Ce travail a porté sur la déstabilisation d’une émulsion d’huile de coupe algérienne (Tasfalout 22/B) par électrocoagulation (EC) en batch en utilisant des électrodes de fer. L’efficacité du procédé est évaluée par la mesure de la turbidité. Une meilleure efficacité de déstabilisation est obtenue par une augmentation de la densité de courant de 50 à 350 A•m‑2 pour un temps d’électrolyse de 15 min et des concentrations en huile de coupe de 1 % (p/p), 2 % (p/p) et 4 %(p/p). Un rendement d’élimination en turbidité de 99 % a été obtenu pour une émulsion à 4 % (p/p), une densité de courant de 150 A•m‑2 et un temps d’électrolyse de 120 min.Le suivi de la cinétique de dissolution de l’électrode de fer sur une période de 120 minutes a montré qu’une même efficacité du procédé peut être obtenue par une diminution du temps d’électrolyse et une augmentation de la densité de courant.Une étude comparative des performances de l’électrocoagulation et de la coagulation-floculation au chlorure ferrique hydraté (FeCl3•6H2O), vis-à-vis de la déstabilisation d’une émulsion d’huile de coupe, a été réalisée. Elle a mis en évidence l’avantage de la coagulation-floculation pour l’émulsion à 1 % (p/p), pour les différentes densités de courant testées en électrocoagulation. Par contre, les rendements d’élimination pour les deux procédés sont sensiblement similaires pour les émulsions plus concentrées (2 % (p/p) et 4 % (p/p)), pour une densité de courant de 150 A•m‑2. Le pH des émulsions obtenu par les deux procédés après le traitement est différent. Le milieu reste alcalin dans l’électrocoagulation et il devient acide dans la coagulation floculation.This work focuses on the breakdown of an Algerian cutting oil emulsion (Tasfalout 22/B) by batch electrocoagulation (EC) using iron electrodes. The efficiency of the process was estimated from turbidity measurements. An improved efficiency of destabilization was obtained by increasing the current density from 50 to 350 A•m‑2, over an electrolysis time of 15 min and using cutting oil concentrations of 1% (w/w), 2% (w/w) and 4% (w/w). Monitoring of the kinetics of the electrode dissolution over a period of 120 min showed that a similar process efficiency was obtained by decreasing the electrolysis time and by increasing the current density. A 99% removal of turbidity was obtained for an emulsion of 4% (w/w) with a current density of 150 A•m‑2 and an electrolysis time of 120 min.A comparison of the performances of electrocoagulation and of coagulation-flocculation with hydrated ferric chloride (FeCl3•6H2O) processes was carried out, with respect to the destabilization of cutting oil emulsion. This comparison highlighted the advantage of the coagulation-flocculation process for the of 1% (w/w) emulsion at different electrocoagulation current densities. However, for a current density of 150 A•m‑2, the removal efficiency of both processes was similar for the emulsion with higher cutting oil concentrations (2% (w/w) and 4% (w/w)). The pH of the emulsion obtained by the two processes following treatmen...

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“…The Effects of Isobutanul Addition on Bubble Size, Gas Holdup, Interfacial Area, Bubble Coalescence, and Transition Concentration in Dispersion Column inhibited, when the liquid phase is not pure component, but a mixture, as has been reported by Marrucci and Nicodemo [9]. Zahradnik et al [10] studied the link the coalescence behavior of bubbles in aqueous electrolyte solutions with the character of gas-liquid beds generated in bubble column reactors and with corresponding values of bubble bed voidage.…”

Section: Introductionmentioning

confidence: 88%

The Effects of Isobutanul Addition on Bubble Size, Gas Holdup, Interfacial Area, Bubble Coalescence, and Transition Concentration in Dispersion Column

Hanna¹,

Abdul-Rahman²

2014

IJMMM

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Abstract-The bubble coalescence and the transition concentration in a dispersion column have been experimentally studied in this study work by adopting isobutanol-water mixture as a liquid phase and air as a gas phase. The experimental work included the following experimental variables; the weight percent of isobutanol in water and superficial gas velocity of air. The using of two distributors single-orifice and multi-orifice, bubble size, gas holdup and gas-liquid interfacial area are measured. The experimental results have showed that the isobutanol transition concentration is successfully correlated as a function of superficial air velocity, c t =0.072079-0.006408U g +0.000425U g 2 -0.00001U g 3 . This equation gives mean deviation of 4.501%.Index Terms-Gas-liquid dispersion column, bubble coalescence, transition concentration. Greek Letters: g = gas holdup  = coalescence percentage, % Manuscript received October 26, 2013; revised March 20, 2014. F. Z. Hanna is with Koya University, Kurdistan Region of Iraq (e-mail: fadi.hanna@koyauniversity.org).R. K. Abdulrahman is with Koya University, Kurdistan Region of Iraq (e-mail: ribwar.abdulrahman@koyauniversity.org). I. INTRODUCTIONThe most important process in a bubble column is the formation of a gas at the sparger. The smaller the bubbles, the larger are the area for mass transfer between the gas and liquid phases. Bubble swarm behavior in a bubble column is mainly determined by the gas superficial velocity (Heijnen and Riet [1]). Bubble size, bubble rise velocity, bubble size distribution, and liquid and bubble velocity profile have a direct bearing on the performance of bubble columns (Shah et al. [2]). Akita and Yoshida [3] determined the bubble size distribution using a photographic technique. The gas was sparger through perforated plates and single-orifice using various liquids (water, aqueous and pure glycol, methanol, carbon tetrachloride). Saxena A. C and Sexena S. C [4] studied the bubble size distribution in bubble column for the air-water system as a function of gas velocity at room temperature in the two bubble columns. High speed cinephotography and fiber optic probe techniques were used to measure bubble size. They suggest that the bubble size may be dependent on column diameter with smaller bubbles for narrower columns. The bubble size appears to be smaller at the column wall than at distance away from the wall. Gas holdup is one of the most important parameters characterizing the hydrodynamics of bubble columns. It can be defined as the percentage by volume of the gas in the two or three phases mixture in the column (Shah et al. [2]). The influence of gas velocity on gas holdup for alcohols aqueous solutions is reported by Posarac and Tekic [5]. They found that gas holdup value increase with increasing gas velocity and depend significantly on the type of alcohol added. Ruzicka et al. [6] studied experimentally the effect of the column size (height and diameter) on the stability of the homogeneous flow regime. The stability was expressed by...

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Coalescence of gas bubbles in aqueous solutions of inorganic electrolytes

Cited by 288 publications

References 24 publications

Modelling the effects of oxygen evolution in the all-vanadium redox flow battery

Modelling the effects of oxygen evolution in the all-vanadium redox flow battery

Étude comparative de l’électrocoagulation et de la coagulation floculation vis-à-vis de la déstabilisation d’une émulsion d’huile de coupe

The Effects of Isobutanul Addition on Bubble Size, Gas Holdup, Interfacial Area, Bubble Coalescence, and Transition Concentration in Dispersion Column

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